Soli water evaporation is the important component of water cycle,as well as the basis of the study on drought resistance
in arid a nd semi-arid regions.Water evaporation and drought resistance of the main soils have been studied in Yuanmou
dry and hot valley,
Yunnan Province. The results showed that the relationship between the cumulative curve of evaporation Q and the duration of evaporation T satisfied the equation:Q=aT￣b,where a=0.60 1.10,b=0.65 0.85.The evaporation process existed with stages.According to the 3 soil moisture constants,which had a great effect on plant growth in the fields, the evaporation process was divided into 3 stages. The soil water was evaporated fast the first and second stages,and the decreasing rate of soil water content exceeded 0.35,in the most,reached 0.63,but the rate of soil moisture loss became low while the soil water content was lower than the wilting coefficient. The water evaporation concerned predominantly with soil texture and structure varied in the different soils, at the evaporative stage of soll available water,duration of evaporation reached 87.8h in haplic leptisois,however,only 32.2h in truncatic dry red soils.The water evaporation resistance was arranged from strong to weak in the region as follow:haplic leptisols,vertic dry red soils,haplic dry red soils,truncatic terric usterts,truncatic dry red soils.The disparity in the drouhgt resistance was great in the different soils. The drought resistance arranged from strong to weak was the same as the water evaporation resistance determined by the proportion of soil water loss.